Blockchain Developer - Base

We are building a stealth-stage consumer platform that combines AI-powered data extraction, a token-based incentive layer, and on-chain data verification. The product is built around a mobile-optimised web application through which users contribute structured, verified real-world data and are rewarded with tokens. We have completed the proof-of-concept phase: a working barcode scanner, multi-image capture flow, AI extraction pipeline, and product database are all in production. The MVP phase adds the blockchain and token reward layer on top of this foundation. The engineer joining this role will not be rebuilding anything that already exists — the scope is additive. Full details of the product, market, and roadmap are shared under NDA during the interview process. Tasks We are looking for an experienced blockchain engineer to own the full blockchain integration scope of our MVP. This is a hands-on, individual contributor role with direct accountability to the founding team. The engagement runs for at least five months, with the possibility of a continued relationship depending on the outcome of the MVP phase. You will work closely with the full-stack developer who built our PoC on integration touchpoints, and you will have direct access to the project management team for architectural decisions. Requirements • Smart contracts: design, write, and deploy an ERC-20 token contract on Base with minting restricted to the backend signing wallet. • Batch jobs: implement a Batch Anchor Job (collect unanchored scans, compute hash, submit on-chain) and a Batch Token Distribution Job (multi-send accrued balances to all eligible wallets). • Backend integration: extend the current schema with models for blockchain status, anchor batches, user wallets, and token rewards via a migration that does not disrupt the live extraction pipeline. Build blockchain status and balance API endpoints. • Frontend wallet layer: integrate wagmi v2 + viem into the existing Next.js frontend. Implement wallet connect/disconnect, token balance display (accrued vs. distributed), and error handling for network mismatch, missing extension, and rejected connections. Scanning must remain functional without a connected wallet. • Security: backend signing key in secrets manager, rate limiting on scan endpoints, no raw message signing from user wallets, and a documented key rotation runbook before mainnet. • QA and load testing: extend the regression suite to cover batch flows and blockchain status transitions; run load tests at 500 and 1,000-product anchor batches. We are currently operating in stealth. Candidates advancing to interviews will be asked to sign a mutual NDA before full project details are disclosed. To apply, please send your CV and a short cover letter to info@appspoon(dot)io, or connect with Chuanshan Huang(https://www.linkedin.com/in/chuanshan-huang-617b23115/) on LinkedIn if you'd like to chat informally first. Find Jobs in Germany on Arbeitnow